1. Field of the Disclosure
The present disclosure relates generally to devices and methods for management of multiple subscriber identities (e.g., multiple subscriber identity modules (multi-SIMs)) in a terminal of a cellular telecommunication network. The disclosure relates more specifically to management of multiple subscriber identity modules for devices capable of communicating using two or more subscriber identities with different group of persons while revealing only a specific SIM/contact number to each group.
2. Description of the Related Art
Wireless communication systems provide various types of communication content such as, for example, voice, data, and so on. Wireless multiple-access communication systems support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices communicate with other mobile devices in peer-to-peer wireless network configurations.
Using a dual SIM or multi SIM phone, the user can manage different SIMs for different group of people. Here, one group of people in a contact list of phone can be associated with one SIM contact number while another group of people can be associated with another SIM contact number. A person belonging to one specific group may know only the SIM contact number with which that specific group is associated while being unaware of the other SIM contact number of the user. The user may desire to use only the SIM contact number associated with a group to communicate with a person in that group and hide the other SIM contact number associated with one or more other groups. It is also possible to have a person be a member in multiple groups and thus be aware of multiple SIM contact numbers of the user associated with the various groups.
For example, a user may group all the people from the user's office as “Office Colleagues” and all the people who are the user's family and friends as “Personal Contacts”. The user of the dual SIM phone assigns SIM1 mobile station international subscriber directory number #1 (MSISDN1) as the user's own identity for communicating with people in “Personal Contacts” and SIM2 MSISDN2 as the user's identity for communicating with people in “Office Colleagues”. The user prefers not to share SIM1 MSISDN1 with office colleagues and likewise prefers not to share SIM2 MSISDN2 with personal contacts unless they are also part of “Office Colleagues” group. The user may share his multiple identities or contact numbers with people who belong to multiple groups.
However with the current design or state of the art, there are cases where the user of a multi-SIM phone is forced to use a SIM contact number associated with one group to communicate with a person associated with another group. In such cases, the user may be forced to divulge the user's SIM/contact/MSISDN used to communicate with one group to a member of another group with which the user uses a different SIM/contact/MSISDN.
As an example, the user's phone may go out of network coverage for SIM1 (MSISDN1) associated with group 1 of contacts and the user needs to reach one of the contacts in group 1. Because the network coverage for SIM2 (MSISDN2) is available, the user uses SIM2 to dial the contact number in group 1. As a result, the person in group 1 gets to know the user's SIM2 (MSISDN2) for group 2 because the user used it in order to call the person in group 1. Similarly, the user may run out of the balance on a pre-paid connection with the network of SIM1 (MSISDN1), thereby requiring the user to use the network of SIM2 (MSISDN2) to make a call with a person in group 1. Once again, the person in group 1 gets to know the user's SIM2 (MSISDN2) intended for group 2.
As another example, the network of SIM1 (MSISDN1) has no circuit-switched (CS) service and the user needs to reach one of the contacts in group 1. Because the network coverage and CS service for SIM2 (MSISDN2) are available, the user uses SIM2 to dial the contact number of group 1. But, by receiving the call, the person in group 1 gets to know the user's SIM2 (MSISDN2) intended for members of group 2. Similarly, if the network rejected the registration or location update of SIM1 (MSISDN1) and the user needed to reach one of the contacts in group 1 and assuming the SIM2 (MSISDN2) is successfully registered with its network, the user would use SIM2 to dial the contact number of the person of group 1, who would thereby know the user's SIM2 (MSISDN2) for group 2.
As yet another example, a user of a dual SIM dual standby (DSDS) phone is using SIM2 (MSISDN2) to talk to a person in group 2 associated with SIM2 (MSISDN2). Suppose the user wants to put the call on hold and check something with a person in group 1 associated with SIM1. As this is a DSDS phone, the SIM1 (MSISDN1) protocol stack is inactive because the user cannot use both SIMs simultaneously to make calls. Hence the user holds the SIM2 (MSISDN2) call and dials the person from group 1, who thereby gets to know the user's SIM2 (MSISDN2) for group 2.
If the user of a DSDS phone wants to have a conference call with two people, one from group 1 and another from group 2, only one SIM/protocol stack can be used to communicate with both. One of the user's SIMs (MSISDNs) for one group is thus exposed to a person from another group.
All of the above cases involving DSDS phones apply to dual SIM dual active phones as well where Protocol Stack1/Radio 1 serves SIM1 exclusively and Protocol Stack2/Radio 2 serves SIM2 exclusively.
When using a DSDS phone, the user forwards the calls from SIM1 (MSISDN1) to SIM2 (MSISDN2) before starting a call on SIM2 (MSISDN2). This is because once the user starts the call on SIM2 (MSISDN2), the SIM1/protocol stack1 gets suspended as there is only a single radio in a DSDS mobile phone. If a person in group 1 calls the user in such a case and the person has Connected Line Identity Presentation (COLP) facility enabled then that person gets to know the SIM2/MSISDN2 of the user during establishment of the forwarded call.
FIG. 1 is a schematic diagram illustrating a “context contamination”, “contact disclosure”, or “contact exposure” scenario in a dual SIM phone. In FIG. 1, the user has a dual SIM phone 102, in which a first user group of personal contacts are stored in a first SIM and a second user group of work contacts are stored in a second SIM. The user of dual SIM phone 102 is unable to contact phone 104 of a contact from the work group with the second SIM and instead makes use of the first SIM which is meant only for the user's personal contacts. In such a case, there may be a contact exposure where the personal details of the user of dual 102 may be compromised and these personal details may be revealed to the work group against the user's desire. The personal details include the name of the user and the phone number of the user meant only for personal contacts.
FIG. 2 is a flow chart illustrating a procedure for managing multiple subscriber identities in a multi-SIM device when there is a mobile originating (MO) call. At step 202, the user dials a number from first user group in the contact list. At step 204, it is checked whether the call is possible with the first SIM or not. If yes, then at step 206, the call is established using the first SIM. If the call from first SIM is not possible in step 204, then at step 208, it is checked whether the call is possible with the second SIM. If the call is not possible with the second SIM, then at step 212, the call fails. If the call is possible with the second SIM in step 208, then at step 210, the call is established using the second SIM but the second SIM calling line ID of the user is also displayed on the device of called party (who is in the first group and not the second group).
FIG. 3 is a flow chart illustrating a procedure for managing multiple subscriber identities in a multi-SIM device when either is a mobile terminating (MT) call. At step 302, the user dials a number from second user group in the contact list using the second SIM. At step 304, all the calls for the first SIM are forwarded to the second SIM, assuming a DSDS phone is being used and there is only a single radio. Further at step 306, the call using the second SIM is established. At step 308, a person/party from the first user group calls the user on the first SIM while the user is already on the call using second SIM. At step 310, the user gets a waiting tone indicating another call has arrived while the user is already on the call established using the second SIM. At step 312, the user puts the call established using the second SIM on hold and receives the call from the calling party of the first user group. At step 314, the second SIM identity of the user is displayed on the device of the calling party from the first user group.
In view of the foregoing, there exists a need for methods, apparatuses, and systems which enable the user of a multi-SIM phone to hide one or more contact numbers from one or more specific groups of people.